1. Field of the Invention
The present invention is related to an axial flow fan and particularly to an axial flow fan, which is capable of increasing flow rate and air pressure.
2. Brief Description of the Related Art
Taiwanese Patent Publication No. 540641 discloses an axial flow type blowing device, entitled “AXIAL FLOW TYPE BLOWING DEVICE FOR INCREASING AIR PRESSURE AND FLOW RATE OF OUTPUT FLUID”, which includes an outer frame base, a rotary device, a fan blade device and an outer frame. The outer frame base has an inlet and an outlet being disposed at two lateral sides thereof respectively. The rotary device is used for driving the blowing device and the fan blade device further includes a hub, a plurality of blades and a plurality of thin flow gain plates. While the rotary device rotates with a preset speed to drive the fan blade device, the thin flow gain plates increase the contact area of the blades with the fluid so as to increase flow rate at the inlet.
However, the thin flow gain plates on the blades of the preceding axial type fan provide limited effect due to the sizes thereof being unable to increase and rotation of the fan blade device being affected so that the flow rate and the air pressure is not much increased even if the thin flow gain plates are provided.